Train tracking problem under moving block condition was studied according to the characteristics of CTCS-4 train operation. A Multi-Agent System (MAS) model of multi-train tracking under moving block condition was built based on multi-Agent theory and the interaction mechanism between the train and the Radio Block Center (RBC) was proposed. The model realized the real-time vehicle ground communication and safe distance control of multi-train tracking. The influences of the speed change in train tracking process and different line initialization density on line traffic were simulated, and corresponding quantitative analysis conclusions were obtained. The simulation results show that the proposed MAS model can realize Complex System (CS) formal description of the train control system in the static and dynamic environment, and accurately describe CTCS-4 train tracking mechanism. The example evaluation results prove the feasibility and effectiveness of the proposed method.